Electrically releasable electric connector



p 7, 1954 c. G. WELLING 2,688,734

ELECTRICALLY RELEASABLEI ELECTRIC CONNECTOR Filed June 12, 1950 "WM-w INVENTOR. (O/W740 6 P/ELL/Nq ATTOPNEY Patented Sept. 7, 1954 UNITED STATES PATENT OFFICE ELE CTRICALLY RELEASABLE ELECTRIC CONNECTOR This invention relates to an electrically releasable electric connector, and more particularly to an electrical plug of the type used in connecting electrical appliances through a socket or wall outlet with a source of electric current, which plug is adapted for quick release by electrically operated means.

In the use of conventional electrical plugs, such as those of the type having prongs which fit into the openings of a socket structure and which are usually attached by a cord to electrical appliances, the plugs are customarily removed by hand from the sockets when disconnecting the appliances. Sockets for the connection of such plugs are frequently located in the wall near the floor and the connecting and disconnecting of the plug requires bending over or stooping, which in the course of frequent use of the plug represents a considerable inconvenience and sometimes works a hardship on the user. To avoid stooping or bending over, the plug is often removed by jerking or pulling on the connecting cord, which is likely to result in disrupting the connections between the cord and plug, breakage of the cord, or otherwise damaging the fixture.

It is an important object of this invention to provide an electrical connector plug embodying electrically operable means for releasing the same from the socket.

Another object of the invention is the provision of an electrical connector plug which can be removed from the socket at a distance therefrom without manipulation of the plug or the connecting cord of the same.

A further object of the invention is to provide an electrical connector plug having electrically operable releasing means incorporated in the body of the plug and switch means connected with the connecting cord at a distance from the plug whereby the plug may be removed from the socket or receptacle by operation of the switch.

A still further object of the invention is the provision of an electrically releasable electric connector of simple design and rugged construction having few working parts and capable of withstanding the rough usage to which such an article is customarily subjected.

The above and other objects and advantages of the invention will best be understood from the following detailed description constituting a specification of the same when taken in conjunction with the annexed drawings, wherein- Figure 1 is a longitudinal central cross-sectional viewof the preferred form of the invention, showing the relationship between the parts of the same;

Figure 2 is a longitudinal cross-sectional view of a modified form of the invention, and,

Figure 3 is a cross-sectional view taken along line 33 of Figure 2.

Referring now to the drawings in greater detail, the preferred form of the invention as shown in Figure 1, comprises an electrical connector plug having a hollow body or housing 10, preferably formed of suitable electrically insulating material, in which electrical contact members 12 are secured in any convenient manner, such as by molding in the material of the housing, the contact members having portions I4 extending from the end of the housing and forming prongs adapted to be inserted into an electrical outlet receptacle or socket of conventional construction, not shown. Connecting screws H5, or other appropriate means may be provided on the contact members [2 whereby the wires I8 of a connecting cord 20 can be conveniently attached to the contact members. A third contact member 22 may be molded or otherwise secured in the housing and provided with a similar connecting screw 24 for the attachment of a third wire 26 of the cord 20, for a purpose later to be made apparent. The cord 20 desirably extends through an opening in a projecting portion 28 of the housing for the protection of the insulation at the end of the cord within the housing.

Within the housing, and preferably, but not necessarily, located close to the end of the same from which the prongs I4 project, there is a solenoid coil 30, into which a core or plunger 32 of suitable magnetic material is adapted to extend. The core or plunger 32 may have at one.

end an enlargement 34 which serves to limit the movement of the core through the coil outwardly of the plug, and also forms a seat for a resilient member 36 surrounding the core and bearing against the end of the coil 30. A cylindrical casing 38 may enclose the core 32 and resilient member 36 and is formed with a closed end 40 adapted for engagement with the enlargement 34 tr; limit movement of the core inwardly of the D s- An extension 42 is preferably secured to the outer end of the core or plunger 32, which extension is formed of suitable insulating material, such as rubber or the like. The extension 42 is desirably of resilient character whereby marring of the socket by contact with the same is avoided and any noise resulting from the ex- 3 tension striking the socket is effectively eliminated.

The solenoid coil 30 is connected at one end by a wire to one of the contact members [2 and at the other end by a wire to the contact member 22.

At a suitable point on the cord at a distance from the plug, a switch 48 is connected between the wire 26 of the cord and one of the wires l8 thereof. This switch may desirably be of the momentary contact type, such for example as that shown in Figure 1, having a moveable element 50 of insulating material on which a short conducting portion 52 is carried, which establishes momentary contact between the contact members 54 and 56 when the element 50 is depressed. A coil spring 58 or other equivalent means surrounds the element 50 bearing against a portion of the switch and a collar 60 on the moveable element to return the same to its initial position after depressing.

The cord 20 may extend beyond the switch 40, for attachment to any desired electrical appliance, or, if more expedient the switch may be incorporated in the appliance for connection in the manner described.

In using the connector plug, the prongs l4 are inserted in a conventional socket or outlet in the customary manner just as in the case of the usual plug connector having similar prongs. When it is desired to remove the plug from the receptacle, the switch element 50 is depressed, momentarily energizing the solenoid coil and thereby moving the core or plunger 32 and projecting the extension 42 against the receptacle between the prongs I 4, and the plug is thus forceably released from the receptacle.

It will be apparent that the size of the solenoid coil and the core may be readily adjusted for the voltage available, to assure positive and rapid removal of the plug from the receptacle. By providing a switch of the momentary contact type, as described, it is also possible to apply a relatively high current to the solenoid coil so that ample force is produced to assure complete release of the plug without any danger of over heating the coil, blowing out fuses or otherwise damaging the electrical system. Thus, the use of the invention in its preferred form is attended by a maximum of safety and convenience.

In the form of the invention shown in Figures 2 and 3, a mechanically projected plunger is employed whose action is controlled by electrical means. This form of the invention may have a hollow body or housing 10, in which electrical contact members 12 are disposed, having portions 14 extending from one end forming prongs to be inserted in a receptacle or socket. Connecting screws 16 are provided in the members 14 for the attachment of wires 18 of an electrical conductor cord 80. There is a third. contact member 82 in the housing having a screw 84 for the attachment thereto of a third wire 86 of the cord 80. The cord 80 may, likewise, extend through an opening in a projecting portion 08 of the casing in order to protect the insulation at the end of the cord in the housing.

Within the housing in a central bore 89 therein, there is an electromagnetic coil 90, which acts upon a pivoted latch member 92 of suitable magnetic material.

A plunger 94 extends into the housing through an opening in the end thereof adjacent the prongs 14, which plunger may be of any suitable material and is preferably provided with atip 95 of rubber or the like. The plunger is hollow and fits over a spring retainer rod 95 extending centrally of the bore 89. The plunger has a collar 98 thereon against which a coil spring I00 is adapted to bear, this spring surrounding the retainer rod 95 and also bearing on the bottom of the bore 89 to urge the plunger outwardly of the housmg.

The latch 92 has a projection I02 thereon extending into the bore 09 for engagement with the collar 98 when the plunger is in retracted position to latch the plunger in the housing, and this projection has a sloping surface 104, upon which the collar 98 may engage to pass the latch when moving into retracted position. A leaf spring I06 urges the latch into its latching position.

The magnetic coil 90 is conveniently connected at one end by a wire I08 to one of the contact members 16, and at its other end by a wire 0 to the contact member 82. I

A switch of any suitable character, not shown,

may be connected between the wire 96 and one of the wires 18, at some convenient point in the length of the cord whereby the coil may be energized.

In making use of the form of the invention just described, the prongs 14 are inserted and pushed into a conventional electrical outlet or receptacle, pressing the plunger 94 into the housing and compressing the coil spring I00 therein, until the collar 98 passes the projection I02 of latch 92, after which the plunger is retained by the latch in retracted position.

When it is desired to remove the plug the switch on cord 80 is operated, energizing the coil 90 and drawing the latch 92 out of contact with the collar 98, whereupon the coil spring I00forces the plunger out of the housing. against the receptacle and removes the plug from the receptacle.

It will be noted that the plunger may be depressed into fully retracted position in the housing, and will be securely latched therein, before the plug is inserted in the receptacle or socket, or the plug may merely be forced into the socket and the plunger thereby depressed at the same time.

The invention as above described affords a simple and entirely safe device whereby an electrical connector plug can be conveniently and positively removed from the socket at a distance, and without the necessity of stooping or bending to reach the same, or subjecting the cord attached to the plug to unnecessary pulling strain.

While the invention has been disclosed in connection with certain specific embodiments of the same, it will be understood that these are by way of illustration only, and numerous changes can be made in the structures of the various parts as well as in the arrangement of the same, without departing from the spirit of the invention and within the scope of the appended claims.

Having thus clearly shown and described the invention, what is claimed as new and desired to secure by Letters Patent is:

1. An electrical connection for plugging into a wall socket or the like comprising a hollow body provided with a pair of prongs for insertion in a socket, a plunger of magnetic material mounted on the body for movement to a projected position extending from the body to exert a thrust against the socket to withdraw the prongs from the socket and to a retracted position within the body, resilient means in the body positioned toi coact with the body and plunger to yieldingly urge the plunger toward retracted position, a normally deenergized electromagnetic coil in the body positioned to attract the plunger to move the plunger toward projected position upon energization of the coil, an electrical conductor connected to each of said prongs and to a utility, one end of said coil being connected to one of said conductors, a manually operable, normally open switch located at a distance from said body and connected to the other of said conductors, and means forming an electrical connection between the other end of said coil and said switch, whereby said coil will be energized upon closing of said switch.

2. An electrical connection for plugging into a wall socket or the like comprising a hollow body provided with a pair of prongs for insertion in a socket, a plunger of magnetic material mounted in the body for movement to a projected position extending from the body to exert a thrust against the socket to withdraw the prongs from the socket and to a retracted position Within the body, resilient means in the body positioned to coact with the body and plunger to yieldingly urge the plunger toward retracted position, a normally deenergized electromagnetic coil in the body positioned to attract the plunger to move the plunger toward projected position upon energization of the coil, a three conductor electrical cord two conductors of which are connected to said prongs, and to a utility, one end of said coil being connected to the third one of said conductors, and manually operable, normally open, switch means, attached to said cord at a distance from said body and. connected to one of said two of said conductors and to said third conductor, the other end of said coil being connected to the other one of said two conductors; whereby said coil will be energized upon closing of said switch means.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 574,025 Edgecomb Dec. 29, 1896 688,382 Bohm Dec. 10, 1901 829,511 Davis Aug. 28, 1906 1,004,860 Eastwood Oct. 3, 1911 1,058,178 Hart Apr. 8, 1913 1,700,228 Kendall Jan. 29, 1929 2,076,136 Weed Apr. 6, 1937 2,186,498 Riggs Jan. 9, 1940 2,259,799 Corrigan Oct. 21, 1941 2,394,618 Kunasch Feb. 12, 1946 

